What is difference between distinct and group by (without aggregate function)

Question

I want to know, for removing duplicate rows, which query is better ? (faster and more optimized):

select distinct col from table;

OR

select col from table group by col;

As you see, there is not any aggregate function , So which one is better ? Or in other word, what is the difference between them ?

Answer 1

GROUP BY lets you use aggregate functions, like AVG, MAX, MIN, SUM, and COUNT. Other hand DISTINCT just removes duplicates.

You can read this answer too : https://stackoverflow.com/a/164544/4227703

Answer 2

Please use DISTINCT for removing duplicate rows, as this construct was specifically designed for this purpose. It's shorter, easier to read and understand.